Vernier tuning dial



March 1, 1927.

' A. w. FRANKLIN VERNIER"TUNING DIAL Filed Feb. 19. 1924 m T m v m ATTORNEY Patented Mar. 1, 1927.

e STATES .A-LBERT w. FRANKLIN, IDEA-NEW roan, at. Y., :AssIenon no .cnnsnnnsnmn no; me,

a Y or N W YORK, n. n, A conronaflon or new YORK.

mama; TUNING" DIAL.

Application fi1ed.Febi'uary'19,-'1924. .Serial No. 893,803.

This inventionrelates to improvements in dials and more particularly tothe type of dial used in connection. with. electrical and like apparatus "in"which"it 'is desirable to obtain precision in setting.

Such accuracy in adjusting the dials had hitherto been attained by expensive and cumbersome methods, as for instance by the use of frictional or toothed gearing, in volving a rotor pinion distinct from the dial,

by slow and tedious screw adjustments necessarily limited in range of action, and divers other devices whlch disfigure the dial and mar the appearance of the panel to' which they are applied.

It is therefore the object of this invention to provide a particularly simple and effective device whereby a dial may be set or reset exactly toany desired point with micrometer precision.

Another purpose is to produce means for adjusting the dial that are wholly unobjectionable in appearance and are incapable of injuring the dial or panel on which it is mounted.

A further aim is in the provision of an adjusting means that can be readily operated without special experience and which in no manner interferes or conflicts with the free and untrammelled twirling of the dial by its knob in obtaining an approximate setting.

These several aims and objects are accomplished by the novel and practical construction and combination of parts hereinafter described and illustrated in the accompanying drawings, forming a material part of this disclosure, and in which Fig. 1 is a bottom plain view of a dial made in accordance with the invention.

Fig. 2 is a transverse sectional view, taken on line 2-2 of Fig, 1, shown as in operative position.

Fig. 3 is a fragmentary sectional view, similar to Fig. 2, but showing a slight modification in construction.

In all of the several views the numeral 10 designates a conventional panel or plate, through which extends a spindle 11 having fixed to it whatever part is to be rotated into adjustment.

The opposite, outer end of the spindle 18 secured in a bushing or sleeve 12, usually made of brass and fixedly embedded in the central hub portion 13 of the dial.

This hub element is integral with the convex face of a knob 14 having aniannular recess 15, to reduce weight the knob: being plain or knurled as preferred, its 'lowervend blending into the face 16 of the dial from which extends a beveled peripheral edge 17.

An annular ring 18 having a level outer surface is at the back of the bevelled edge 17, the ring enclosing a recess 19 into which the recess 15 opens, thus reducing the thickness, and correspondingly the weight, of' the material of the dial, which ma be of hard rubber, bakelite or similar dielectric substance.

The foregoing is substantially descriptive of any ordinary type of'dial and it will be understood that graduations, scales, numerals or other marks may be borne on the elements 16 and 17 as is usual.

In carrying out the invention, one or moreradial, inreaching blocks 20 extend level from the face of the ring 18 to an annular depression 21 in the back of the dial and formed through the block and face 16 is a narrow elongated slot 22, tangent to the axis of the dial.

A recess 24 extends into the bevelled portion 17 of the dial, at a point registering with the center of the slot 22, and extending from the recess 23 into the annular recess 21, parallel with the base of the dial, is an opening in which is engaged a screw 24 or pin if preferred, acting as a. pivot support for a roller 25.

The diameter of this roller and its position, 'is such that its periphery extends slightly below the level of the base of the dial and also above the upper face 16, the roller being provided with a relatively soft rubber covering over its rounded edge for the double purpose of affordingan effective frictional contact with an operators fingers in maneuvering it, and also to prevent marring the surface below the dial on which the roller impinges.

In the modification shown in Fig. 3, the 100 slot 22 in the face of the dial opens at the bottom into a rectangular recess 26 suited justed by placing finger on the roller and rotating it as mat be necessar Although the foregoing is escriptiveof specific embodiments of the invention, it will be understood that the appended claims Will cover minor changes regarding the roller constructions, mounting, number used, sizes, proportions and like inconsequential details. a Having described my invention, what I claim as new and desire to secure by Letters Patent is a 1. A dial having a depression or pocket in its rear face adaptedto receive the trunnions of a roller and having an elongated slot through which said roller may operate.

2. The combination with a dial having a recess in its rear face, and aelot eommunicating therewith of a trunnioned roller journalled in said recess and extending through said slot.

Signed at New York in the county of New York and State OfNBW' York this 4th day of February A. D. 1924.

ALBERT W. FRANKLIN. 

